ASROCK Z390 Instruction Manual page 22

2.4 Expansion Slots (PCI Express Slots)
There are 6 PCI Express slots on the motherboard.
Before installing an expansion card, please make sure that the power supply is
switched off or the power cord is unplugged. Please read the documentation of the
expansion card and make necessary hardware settings for the card before you start
the installation.
PCIe slots:
PCIE1 (PCIe 3.0 x1 slot) is used for PCI Express x1 lane width cards.
PCIE2 (PCIe 3.0 x16 slot) is used for PCI Express x16 lane width graphics cards.
PCIE3 (PCIe 3.0 x1 slot) is used for PCI Express x1 lane width cards.
PCIE4 (PCIe 3.0 x16 slot) is used for PCI Express x8 lane width graphics cards.
PCIE5 (PCIe 3.0 x1 slot) is used for PCI Express x1 lane width cards.
PCIE6 (PCIe 3.0 x1 slot) is used for PCI Express x1 lane width cards.
PCIe Slot Configurations
Single Graphics Card
Two Graphics Cards in
CrossFireX
Mode
For a better thermal environment, please connect a chassis fan to the motherboard's
chassis fan connector (CHA_FAN1/WP, CHA_FAN2/WP or CHA_FAN3/WP) when using
multiple graphics cards.
20
PCIE2
x16
TM TM
x8
or SLI
PCIE4
N/A
x8